1. Field of the Invention
The present invention relates to an adhesive sheet for manufacturing a semiconductor device, a manufacturing method of a semiconductor device using the sheet, and a semiconductor device obtained by the method.
2. Description of the Related Art
In order to correspond to the demand of microminiaturization and realization of high functionality of a semiconductor device, the wiring width of a power line and the interval between signal lines arranged on the entire area of the major surface of a semiconductor chip (a semiconductor element) have been becoming narrow. Thereby, an increase of impedance and interference of signals between signal lines of different nodes occur, which become the cause of impeding the demonstration of sufficient performance in operation speed, degree of allowance in operation voltage, anti-electrostatic breakdown strength, and the like in the semiconductor chip. In order to solve these problems, a package structure is proposed in which the semiconductor element is layered (for example, refer to Japanese Patent Application Laid-Open (JP-A) Nos. 55-111151 and 2002-261233).
On the other hand, as a substance used when a semiconductor element is fixed onto a substrate or the like, an example using a thermosetting paste resin (for example, refer to JP-A No. 2002-179769) and an example using an adhesive sheet in which a thermoplastic resin and a thermosetting resin are combined (for example, refer to JP-A Nos. 2002-261233 and 2000-104040) are proposed.
In the conventional manufacturing method of a semiconductor device, an adhesive sheet or an adhesive is used at the time of adhesion of a semiconductor element and a substrate, a lead frame, or a semiconductor element. The adhesion is performed by compression bonding (die attaching) a semiconductor element and a substrate or the like, and then by curing an adhesive sheet or the like in a heating step. Further, wires are bonded to connect the semiconductor element and the substrate electrically, and then sealing with a sealing resin is performed by molding with the sealing resin and curing (for example, refer to JP-A Nos. 2002-261233 and 2000-104040).
When the above-described wire-bonding is performed, the semiconductor element on the substrate or the like moves due to ultrasonic vibration and heating. Because of this, conventionally, there has been a necessity to fix the semiconductor element so as not to move by heating and curing the thermosetting paste resin and the thermosetting adhesive sheet through a heating step before the wire bonding.
Furthermore, for the adhesive sheet consisted of a thermoplastic resin and the adhesive sheet in which a thermosetting resin and a thermoplastic resin are combined, a heating step is necessary after the die attaching and before the wire-bonding for the purpose of ensuring adhesive strength with an adhesion target and improving wettability.
However, in the case that air bubbles, foreign objects, or the like are mixed in when this adhesive sheet is adhered to a semiconductor element (a wafer) or a semiconductor chip made into an individual piece with a method such as a roller method or vacuum pasting, this adhesive sheet cannot be peeled off nor removed from the semiconductor element or the semiconductor chip made into an individual piece, and the semiconductor element and the like have been wasted. Because of this, production cost has been high and a decrease of the yield has been brought about.